1. Field of the Invention
The invention relates to a process for providing a binder for mineral fibers, i.e. man made vitreous fibers, for example glass, slag or stone wool, a binder obtainable via such a process, and a mineral wool product comprising such a binder.
2. Description of the Related Art
Mineral wool products generally comprise mineral fibers bonded together by a cured thermoset polymeric material. One or more streams of molten glass, slag or stone are drawn into fibers and blown into a forming chamber where they are deposited as a web on to a travelling conveyer. The fibers, while airborne in the forming chamber and while still hot are sprayed with a binder. The coated fibrous web is then transported from the chamber to a curing oven where heated air is blown through the mat to cure the binder and rigidly bond the mineral wool fibers together.
Phenol-formaldehyde binders are widely used in the mineral wool industry since they have a low viscosity in the uncured state, yet still form a rigid thermoset polymeric matrix for the mineral fibers when cured.
However the use of phenol formaldehyde binders is becoming increasingly undesirable due to the use and release of environmentally unfavourable chemicals during the process.
The use of β-hydroxyalkylamides to cure polycarboxy polymers such as polyacrylic acid in order to provide a binder is known.
A problem with polyacrylics cured by β-hydroxyalkylamides is that mineral wool products bound with such a resin normally exhibit good mechanical properties before ageing, but after exposure to high humidities and increased temperatures, for example above 40 degrees centigrade, the mechanical properties are drastically reduced.
There is therefore a desire to develop a binder which improves on the known binders.